Predicting Sudden Death in the General Population

Despite increased awareness and advances in resuscitation methodology, the average national survival from sudden cardiac arrest in North America remains 4.5%, ranging from 1.1% in the state of Alabama to 8.1% in Seattle, Wash.1 Given this 95% probability of instantaneous death once cardiac arrest occurs, the pursuit to identify effective preventive interventions must be unrelenting. The implantable cardioverter-defibrillator has been an effective modality that treats the crisis, but methodologies for effective risk stratification of the actual condition continue to elude us.2 The left ventricular ejection fraction can be a reasonable means of risk stratification in a subgroup of sudden cardiac death (SCD) patients but is clearly an inadequate predictor of overall risk.3 Some mechanisms of SCD risk are likely to overlap between men and women,4 but there is growing evidence to suggest that there may also be sex-specific pathways leading to ventricular arrhythmogenesis.5,6 A recent study in a Medicare population sample (1991 to 2005) found that men were significantly more likely to undergo cardioverter-defibrillator implantation for both primary and secondary prevention of SCD (hazard ratio 3.15, 95% confidence interval 2.86 to 3.47, and hazard ratio 2.44, 95% confidence interval 2.30 to 2.59, respectively),7 and this disparity between the sexes has also been reported in 2 other studies.8,9 Therefore, the identification of sex-specific SCD mechanisms is a crucial element …